On 01/09/2014 04:15 PM, MauMau wrote: > From: "Hannu Krosing" <ha...@2ndquadrant.com> >> On 01/09/2014 01:57 PM, MauMau wrote: >>> Let me ask a (probably) stupid question. How is the sync rep >>> different from RAID-1? >>> >>> When I first saw sync rep, I expected that it would provide the same >>> guarantees as RAID-1 in terms of durability (data is always mirrored >>> on two servers) and availability (if one server goes down, another >>> server continues full service). >> What you describe is most like A-sync rep. >> >> Sync rep makes sure that data is always replicated before confirming to >> writer. > > Really? RAID-1 is a-sync? Not exactly, as there is no "master" just controller writing to two equal disks.
But having a "degraded" mode makes it more like async - it continues even with single disk and syncs later if and when the 2nd disk comes back. Cheers -- Hannu Krosing PostgreSQL Consultant Performance, Scalability and High Availability 2ndQuadrant Nordic OÜ -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
